In the related art, a projector including a light source, an optical modulation device which modulates light emitted from the light source according to image information, and a optical projection device which projects light modulated by the optical modulation device is known. The optical projection device is configured to include the plurality of lens groups. A projection lens (optical projection device) including a lens group configured to be able to move along an optical axis among a plurality of lens groups is suggested (for example, see PTL 1).
The projection lens described in PTL 1 includes a guide barrel having a straight movement groove, a cam barrel having a cam groove, a first lens group to a seventh lens group, and a plurality of lens frames. Among the plurality of lens frames, there is a front lens frame holding a fourth lens group, an intermediate lens frame holding a fifth lens group, and a rear lens frame holding a sixth lens group. The intermediate lens frame is disposed between the front lens frame and the rear lens frame and the rear lens frame is fixed to the front lens frame.
Each of the front lens frame and the intermediate lens frame has cam pins engaging with the cam groove and the cam pins are supported on the cam groove and disposed thereon. The cam pins which sandwich the intermediate lens frame therebetween are formed on one side of the front lens frame in a direction along the optical axis, the front lens frame holds the fourth lens group in the vicinity of the cam pins, and the rear lens frame is fixed to the other side of front lens frame.
When the cam barrel is rotated, the cam pins are guided to a straight movement groove and the cam groove and thus, the front lens frame and the intermediate lens frame are moved independently of each other. Since the rear lens frame is fixed to the front lens frame, the front lens frame and the rear lens frame are integrally moved in a state of respectively holding the fourth lens group and the sixth lens group.